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Shao Y, Yang S, Li J, Cheng L, Kang J, Liu J, Ma J, Duan J, Zhang Y. Compound heterozygous mutation of the SNX14 gene causes autosomal recessive spinocerebellar ataxia 20. Front Genet 2024; 15:1379366. [PMID: 38655056 PMCID: PMC11035801 DOI: 10.3389/fgene.2024.1379366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 03/20/2024] [Indexed: 04/26/2024] Open
Abstract
Objective: The article aims to provide genetic counseling to a family with two children who were experiencing growth and developmental delays. Methods: Clinical information of the proband was collected. Peripheral blood was collected from core family members to identify the initial reason for growth and developmental delays by whole exome sequencing (WES) and Sanger sequencing. To ascertain the consequences of the newly discovered variants, details of the variants detected were analyzed by bioinformatic tools. Furthermore, we performed in vitro experimentation targeting SNX14 gene expression to confirm whether the variants could alter the expression of SNX14. Results: The proband had prenatal ultrasound findings that included flattened frontal bones, increased interocular distance, widened bilateral cerebral sulci, and shortened long bones, which resulted in subsequent postnatal developmental delays. The older sister also displayed growth developmental delays and poor muscle tone. WES identified compound heterozygous variants of c.712A>T (p.Arg238Ter) and .2744A>T (p.Gln915Leu) in the SNX14 gene in these two children. Both are novel missense variant that originates from the father and mother, respectively. Sanger sequencing confirmed this result. Following the guideline of the American College of Medical Genetics and Genomics (ACMG), the SNX14 c.712A>T (p.Arg238Ter) variant was predicted to be pathogenic (P), while the SNX14 c.2744A>T (p.Gln915Leu) variant was predicted to be a variant of uncertain significance (VUS). The structural analysis revealed that the c.2744A>T (p.Gln915Leu) variant may impact the stability of the SNX14 protein. In vitro experiments demonstrated that both variants reduced SNX14 expression. Conclusion: The SNX14 gene c.712A>T (p.Arg238Ter) and c.2744A>T (p.Gln915Leu) were identified as the genetic causes of growth and developmental delay in two affected children. This conclusion was based on the clinical presentations of the children, structural analysis of the mutant protein, and in vitro experimental validation. This discovery expands the range of SNX14 gene variants and provides a foundation for genetic counseling and guidance for future pregnancies in the affected children's families.
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Affiliation(s)
- Yuqi Shao
- Department of Obstetrics, Zhongnan Hospital of Wuhan University, Wuhan, China
- Hubei Clinical Research Center for Prenatal Diagnosis and Birth Health, Wuhan, China
| | - Saisai Yang
- Department of Obstetrics, Zhongnan Hospital of Wuhan University, Wuhan, China
- Hubei Clinical Research Center for Prenatal Diagnosis and Birth Health, Wuhan, China
| | - Jiafu Li
- Department of Obstetrics, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Lin Cheng
- Department of Obstetrics, Zhongnan Hospital of Wuhan University, Wuhan, China
- Hubei Clinical Research Center for Prenatal Diagnosis and Birth Health, Wuhan, China
| | - Jiawei Kang
- Department of Obstetrics, Zhongnan Hospital of Wuhan University, Wuhan, China
- Hubei Clinical Research Center for Prenatal Diagnosis and Birth Health, Wuhan, China
| | - Juan Liu
- Department of Obstetrics, Zhongnan Hospital of Wuhan University, Wuhan, China
- Hubei Clinical Research Center for Prenatal Diagnosis and Birth Health, Wuhan, China
| | - Jianhong Ma
- Department of Obstetrics, Zhongnan Hospital of Wuhan University, Wuhan, China
- Hubei Clinical Research Center for Prenatal Diagnosis and Birth Health, Wuhan, China
| | - Jie Duan
- Department of Obstetrics, Zhongnan Hospital of Wuhan University, Wuhan, China
- Hubei Clinical Research Center for Prenatal Diagnosis and Birth Health, Wuhan, China
| | - Yuanzhen Zhang
- Department of Obstetrics, Zhongnan Hospital of Wuhan University, Wuhan, China
- Hubei Clinical Research Center for Prenatal Diagnosis and Birth Health, Wuhan, China
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Sharmin T, Takuma T, Morshed S, Ushimaru T. Sorting nexin Mdm1/ SNX14 regulates nucleolar dynamics at the NVJ after TORC1 inactivation. Biochem Biophys Res Commun 2021; 552:1-8. [PMID: 33740659 DOI: 10.1016/j.bbrc.2021.03.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 03/07/2021] [Indexed: 11/20/2022]
Abstract
The degradation of nucleolar proteins - nucleophagy - is elicited by nutrient starvation or the inactivation of target of rapamycin complex 1 (TORC1) protein kinase in budding yeast. Prior to nucleophagy, nucleolar proteins migrate to the nucleus-vacuole junction (NVJ), where micronucleophagy occurs, whereas rDNA (rRNA gene) repeat regions are condensed and escape towards NVJ-distal sites. This suggests that the NVJ controls nucleolar dynamics from outside of the nucleus after TORC1 inactivation, but its molecular mechanism is unclear. Here, we show that sorting nexin (SNX) Mdm1, an inter-organelle tethering protein at the NVJ, mediates TORC1 inactivation-induced nucleolar dynamics. Furthermore, Mdm1 was required for proper nucleophagic degradation of nucleolar proteins after TORC1 inactivation, where it was dispensable for the induction of nucleophagic flux itself. This indicated that nucleophagy and nucleolar dynamics are independently regulated by TORC1 inactivation. Finally, Mdm1 was critical for survival during nutrient starvation conditions. Mutations of SNX14, a human Mdm1 homolog, cause neurodevelopmental disorders. This study provides a novel insight into relationship between sorting nexin-mediated microautophagy and neurodevelopmental disorders.
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Shukla A, Upadhyai P, Shah J, Neethukrishna K, Bielas S, Girisha KM. Autosomal recessive spinocerebellar ataxia 20: Report of a new patient and review of literature. Eur J Med Genet 2016; 60:118-123. [PMID: 27913285 DOI: 10.1016/j.ejmg.2016.11.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 11/10/2016] [Accepted: 11/20/2016] [Indexed: 10/20/2022]
Abstract
Inherited ataxias are an extremely heterogeneous group of disorders. Autosomal recessive spinocerebellar ataxia 20 (SCAR20) is a recently described disorder characterized by intellectual disability, ataxia, coarse facial features, progressive loss of Purkinje cells in the cerebellum and often hearing loss and skeletal abnormalities. Mutations in the gene SNX14, which plays an important role in autophagy, have been found to cause SCAR20. The unique clinical findings of progressive coarsening of facial features makes the clinical phenotype recognizable among the various hereditary ataxias. Here we report on a child with a novel missense mutation in the SNX14 gene that appears to be debilitating for protein conformation, function and review the previously reported cases from 15 families.
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Affiliation(s)
- Anju Shukla
- Department of Medical Genetics, Kasturba Medical College, Manipal University, Manipal, India
| | - Priyanka Upadhyai
- Department of Medical Genetics, Kasturba Medical College, Manipal University, Manipal, India
| | - Jhanvi Shah
- Department of Medical Genetics, Kasturba Medical College, Manipal University, Manipal, India
| | - K Neethukrishna
- Department of Medical Genetics, Kasturba Medical College, Manipal University, Manipal, India
| | - Stephanie Bielas
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - K M Girisha
- Department of Medical Genetics, Kasturba Medical College, Manipal University, Manipal, India.
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Ha CM, Park D, Kim Y, Na M, Panda S, Won S, Kim H, Ryu H, Park ZY, Rasenick MM, Chang S. SNX14 is a bifunctional negative regulator for neuronal 5-HT6 receptor signaling. J Cell Sci 2015; 128:1848-61. [PMID: 25795301 DOI: 10.1242/jcs.169581] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Accepted: 03/13/2015] [Indexed: 02/01/2023] Open
Abstract
The 5-hydroxytryptamine (5-HT, also known as serotonin) subtype 6 receptor (5-HT6R, also known as HTR6) plays roles in cognition, anxiety and learning and memory disorders, yet new details concerning its regulation remain poorly understood. In this study, we found that 5-HT6R directly interacted with SNX14 and that this interaction dramatically increased internalization and degradation of 5-HT6R. Knockdown of endogenous SNX14 had the opposite effect. SNX14 is highly expressed in the brain and contains a putative regulator of G-protein signaling (RGS) domain. Although its RGS domain was found to be non-functional as a GTPase activator for Gαs, we found that it specifically bound to and sequestered Gαs, thus inhibiting downstream cAMP production. We further found that protein kinase A (PKA)-mediated phosphorylation of SNX14 inhibited its binding to Gαs and diverted SNX14 from Gαs binding to 5-HT6R binding, thus facilitating the endocytic degradation of the receptor. Therefore, our results suggest that SNX14 is a dual endogenous negative regulator in 5-HT6R-mediated signaling pathway, modulating both signaling and trafficking of 5-HT6R.
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Affiliation(s)
- Chang Man Ha
- Department of Physiology and Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799, South Korea Biomembrane Plasticity Research Center, Seoul National University College of Medicine, Seoul 110-799, South Korea Department of Structure and Function of Neural Network, Korea Brain Research Institute, Daegu 700-100, South Korea
| | - Daehun Park
- Department of Physiology and Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799, South Korea Biomembrane Plasticity Research Center, Seoul National University College of Medicine, Seoul 110-799, South Korea
| | - Yoonju Kim
- Department of Physiology and Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799, South Korea Biomembrane Plasticity Research Center, Seoul National University College of Medicine, Seoul 110-799, South Korea Neuroscience Institute, Seoul National University College of Medicine, Seoul 110-799, South Korea
| | - Myeongsu Na
- Department of Physiology and Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799, South Korea Biomembrane Plasticity Research Center, Seoul National University College of Medicine, Seoul 110-799, South Korea
| | - Surabhi Panda
- Departments of Physiology & Biophysics and Psychiatry, University of Illinois at Chicago, Jesse Brown VA Medical Center, Chicago, IL 60680, USA
| | - Sehoon Won
- Department of Life Science, Gwangju Institute of Science and Technology, Gwangju 500-712, South Korea
| | - Hyun Kim
- Department of Anatomy, Korea University College of Medicine, Seoul 136-705, South Korea
| | - Hoon Ryu
- Biomembrane Plasticity Research Center, Seoul National University College of Medicine, Seoul 110-799, South Korea
| | - Zee Yong Park
- Department of Life Science, Gwangju Institute of Science and Technology, Gwangju 500-712, South Korea
| | - Mark M Rasenick
- Departments of Physiology & Biophysics and Psychiatry, University of Illinois at Chicago, Jesse Brown VA Medical Center, Chicago, IL 60680, USA
| | - Sunghoe Chang
- Department of Physiology and Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799, South Korea Biomembrane Plasticity Research Center, Seoul National University College of Medicine, Seoul 110-799, South Korea Neuroscience Institute, Seoul National University College of Medicine, Seoul 110-799, South Korea
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